Many telephone sets, particularly those used in business, are provided with an internal microphone for handsfree operation, this typically taking the form of a microphone housing incorporated into the telephone set, the housing defining an opening to the exterior, the opening communicating the exterior with an internal cavity within which is located an internal microphone. Leads connect the internal microphone with an adjacent printed circuit board (PCB).
It is desirable to increase the acoustic performance of a handsfree telephone set. For example, in typically noisy or acoustically xe2x80x9clivexe2x80x9d environments, it is expected to be of substantial benefit to disconnect or disable the internal handsfree microphone normally supplied along with the telephone set, and to attach instead an external microphone which can be positioned in a preferred location. It has been found that increasing the acoustic separation between the microphone and the speaker makes full duplex handsfree algorithms much more effective.
Finding a way for this to occur has been a challenge in the industry, since it is desirable to avoid increasing the cost of the product. For example, prior art methods for providing this versatility have involved the provision of a separate connector in a physically different place on the product. Thus, the product would have the conventional opening leading to the on-board microphone, along with a separate connectorxe2x80x94a complication that increases the cost of manufacture.
The procedure to be described below allows either a) a microphone to be used in a regular half-duplex speaker phone or b) a full duplex speaker phone telephone set, without any modification of the external plastic housing.
More particularly, this invention provides, in a telephone set which includes a microphone housing defining an opening that communicates with a cavity in the microphone housing within which is located an internal microphone, and leads connecting the internal microphone with a PCB, the improvement comprising:
an external microphone connected to a plug which is receivable snugly within said opening, thereby to substantially block external sound from reaching said internal microphone, and contact means linking the PCB with portions of the plug and thus with the external microphone.
In addition, this invention provides, in combination, a telephone set which includes a microphone housing defining an opening which communicates with a cavity in the microphone housing, an internal microphone located in said cavity, leads connecting the internal microphone with a PCB, and an external microphone connected to a plug receivable snugly within said opening, thereby to substantially block external sound from reaching the internal microphone, and contact means linking the PCB with portions of the plug, and thus with the external microphone.
Further, this invention provides a method of increasing the microphone options for a telephone set, the telephone set including a microphone housing defining an opening which communicates the exterior with a cavity in the microphone housing within which is located an internal microphone, and leads connecting the internal microphone with a PCB, said method including:
a) providing an external microphone connected to a plug which is receivable within said opening snugly enough to substantially block external sound from reaching said internal microphone,
b) providing contact means for linking the PCB with portions of the plug and thus with the external microphone,
c) inserting the plug into the opening whenever it is desired to use said external microphone, and
d) removing the plug from the opening whenever it is desired to use said internal microphone.